SMS Castle of Illusion: Starring Mickey Mouse (USA/Europe V.1.1) in 12:48.54 by Tee-N-Tee.
Tee-N-Tee has improved 52.8 seconds over the previous run by several new tricks, like preserving speed after coming off of a slope, and a new shortcut. You can see details on all of these things in his write-up.